Enum VarExpandError 

#[non_exhaustive]
pub enum VarExpandError {
    MissingVariable {
        name: String,
        offset: usize,
    },
    InvalidVariableName {
        got: String,
        offset: usize,
    },
    UnclosedBraceExpansion {
        offset: usize,
    },
    UnclosedPercentExpansion {
        offset: usize,
    },
    EmptyBraceExpansion {
        offset: usize,
    },
}

Errors produced by crate::vars::expand.

Each variant is designed to be self-describing when rendered through Display (via thiserror), so eprintln!("{err}") is sufficient for a CLI diagnostic. The offset field always points at the first byte of the offending placeholder ($, ${, or %), never inside it.

Marked #[non_exhaustive] so new diagnostic variants can land without breaking external match sites.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

MissingVariable

A well-formed placeholder referenced a variable name that was not present in the crate::vars::VarEnv.

Fields

name: String

Variable name as written in the input.

offset: usize

Byte offset of the opening sigil ($ or %).

InvalidVariableName

A placeholder contained a name that does not match ^[A-Za-z_][A-Za-z0-9_]*$.

Fields

got: String

Raw name bytes as scanned from the input (lossy if non-UTF-8).

offset: usize

Byte offset of the opening sigil.

UnclosedBraceExpansion

A ${ placeholder was never closed with } before end of input.

Fields

offset: usize

Byte offset of the opening $.

UnclosedPercentExpansion

A % opening sigil was never matched by a closing % before end of input.

Fields

offset: usize

Byte offset of the opening %.

EmptyBraceExpansion

A braced placeholder had an empty name: ${}.

Fields

offset: usize

Byte offset of the opening $.

Trait Implementations

impl Debug for VarExpandError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for VarExpandError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for VarExpandError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for VarExpandError

fn eq(&self, other: &VarExpandError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for VarExpandError

impl StructuralPartialEq for VarExpandError